An estimated 56,000,000 American adults have hypertension and millions more with high-normal blood pressure (diastolic 85-89 mm Hg) are at risk for developing it. Dietary sodium restriction has been advocated for the primary or adjunctive treatment of essential hypertension but practical and effective methods for achieving this goal have not been demonstrated in primary care settings. We propose to demonstrate that the intensive dietary instructional and supportive system developed in our current project and used in a university-based setting for reducting the dietary sodium intake of patients with essential hypertension to 80 mEq or less, can be modified and effectively applied to patients with high-normal (diastolic 85-89 mm Hg) and elevated blood pressure (diastolic greater than 89 mm Hg) seen in general medical practice settings. The study will be conducted in a large health maintenance organization and will determine whether intensive dietary instruction given by a dietitian is necessary to achieve and maintain compliance with a low sodium diet. Over 5 years, 408 patients with essential hypertension and 108 high- normals will each be randomly assigned to 1 of 4 groups: 1) face- to-face counseling with a dietitian with dietitian-initiated follow- up support, 2) self-management of dietary sodium reduction through the use of self-instructional materials and access to a dietitian via a low-sodium hot-line telephone, 3) self-management of dietary sodium reduction through the use of self-instructional materials and the use of a quantitative titrator strip for daily urine home-monitoring for feedback on dietary compliance, and 4) a no-instruction control group which, like the other groups, will collect 24-hour urines and receive feedback on their sodium content. In addition, a prediction model will be developed and validated to identify those people most likely to achieve and maintain dietary compliance through self-management. The majority of patients with essential hypertension and high- normal blood pressure are cared for by physicians in general practice settings. The proposed study will demonstrate that dietary instructional and supportive systems can be tailored to be feasible and effective in such settings.